Polyolefin compositions containing certain 2-hydroxy-4-alkoxy benzophenones



United Sta tes Patenff) POLYOLEFIN COMPOSITIONS CONTAINING CER- TAIN 2-HYDROXY-4-ALKOXY BENZOPHENONES 4-dodecyloxy benzophenone, by reacting 25 g. (0.09 mole) of l-bromotetradecane with 19.5 g. 0.09 mole) of 2,4-

Gerald R. Lappin and John W. Tamblyn, Kingsport, i i

Tenn., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey No Drawing. Application November 7, 1957 Serial No. 694,906

12 Claims. (Cl. 260-4595) cause of exudation, discoloration on exposure, or for' some other reason.

We have discovered that 2-hydroxy-4-dodecyloxy benzophenone,

and 2-hydroxy-4-tetradecyloxy benzophenone are compatible with various types of polyethylene and with polypropylene, and give excellent stabilization of these plastics against the deteriorating efiects of ultraviolet light, without discoloration or exudation.

2-hydroxy-4-alkoxy benzophenones in which the al-' koxy group contains or less carbon atoms, or 16 or more carbon atoms, were found tobe incompatible with polyethylene, exuding when used in amounts of only 1 part of the 2-hydr0xy-4-alkoxy benzophenone per 100 parts of polyethylene. It was therefore very surprising to find that 2-hydroxy-4-dodecyloxy benzophenone and 2-hydroxy-4-tetradecyloxy benzophenone are compatible with polyolefins. It may be assumed that 2-hydroxy-4- tridecyloxy benzophenone is also compatibleand operative as astabilizer.

We have prepared 2-hydroxy-4-dodecyloxy-benzophenone and 2-hydroxy-4-tetradecyloxy benzophenone in the following manner. a

PREPARATION OF 2 HYDROXY 4 DODECYL- OXY-BENZOPHENONE A mixture of 100 g. (0.40 mole) of l-bromododecane,

85 g. (0.40 mole) of 2,4-dihydroxybenzophenone, 80 g,

of 'potassiumcarbonate, and 500 ml. of acetone was refluxed with stirring for 24 .hours.

zation from ethanol gave 102 g. of pale yellow crystals,

with a melting point of 43-44" C. The yield was 67%.

of theoretical. Analysisi Calculated for C H O C, 78.5%; H,'8.9%. Found: C, 78.5%; H, 8.93%..

2hydroxy-4-tetradecyloxy benzophenone was prepared in a manner analogousto the preparation of 2 lzvqgdroxy:,

The reaction mix-j ture was poured into 2 l. of water and cooled to 10C., and the product was separated by filtration. Recrystalli subjected to outdoor exposure.

carbonyl groups on exposure was measured by ditference,

dihydroxybenzophenone. 29 g. of pale yellow crystals was obtained, melting at 3839 C. The yield was 78.5% of theoretical. Analysis: Calculated for C H O C, 79.02%; H, 9.27%. Found: C, 79.16%; H, 9.28%.

In testing the stabilizing eifect of our we have proceeded as follows. v r

decyloxy benzophenone was mixed into 100 parts by weight of polyethylene of, melt index 2.(A. S.'-T.",M.. D1238+5 2T) on hot compounding rolls, the' frontfi'oll' being held at 270 F. and the rear roll at 220 F. After 4 minutes rolling the rolled slab was pressed at 285 F. into sheets of 0.060 inch "thickness. These sheets were before and after exposure, ininfrared absorptionin the 5.82, region. The results listed in Table I show clearly the effectiveness of 2-hydroxy-4-dodecyloxy benzophenone in suppressing the undesirable photo-oxidation.

Exampl 2.A second series of polyethylen compo sitions, prepared and sheeted in a similar manner, were subjected to outdoor exposure; The amount of 2 -hy droxy-4-dodecylo'xy benzophenone was again 1 part to.

a 100 parts of polyethylene. The polyethylene also had a tangles 1.5 inch x 0.5 inch were cut from thesesheets, bent into U-shape in aluminum channels and exposed outdoors in this stressed condition, with the stressed side melt index of 2. Table II shows the results.

Example 3.-The compositions of Examplel were compression-molded into sheets /sj inch in thickness. .Rec-

toward the light.- Ten samples of each composition-were mounted-in thisway. Observations were made every few days for the onset of cracking in the stressed region of the specimens. In Table IH the number of days ex posure'required to produce cracks in 5 of the 10 specimens is recorded as thestress-cracking resistance.

' Table 1 novel stabilizers,f

Example 1.-0ne part by weight of 2-hydroxy-4-do -f;

The development of,

Oarbonylformation(arbitrary units) after exa Color posure of- Stabilizer Exudation 131 1 18 Before Aiter days lyear months expoexposure sure None 56 None. None.. None. 4-dodecy1oxy-2- 4 4 9 (ln do Do.

hydroxy-benzophenone.

1 Too high to measure.

Table II Carbonylformmation (arbitrary units) Color" after exposure Stabilizer of Exu- I dation Before After 31days 69days expoexposure sure None 7 17 None- None. None;- 4-dodecy10xy-2-hydroxy- 0.0 0.0 o do-. .Do. benzophenone.

'Table In Table VI Stress- Percent original Exposure cracking elongation retained required for resistance after exposure develop- (exposnre 5 Stabilizer oi ment of Stabilizer time in Ex'udation brittledaysreness (hr.)

quired to 400 hr. 800 hr. crack half the samples None 11 0 8 10 4-dodeoyloxy-2hydroxy-benao- 108 85 2,500 phenone. fd deeylo 2-h droxy ben hi" e 0 xyy zop on o. Table VI] Example 4.--The 0.060-inch sheets described in Ex- 7 ample 1 were examinedfor tensile properties after 14.5 Percent original months exposure. The percent elongation was measured elongation by means of the Instron Tensile Tester. The results of Slammer gg gf these tests are shown in Table 4. It will be observed that 6 months the elongation of the unstabilized polyethylene falls off exposure very rapidly on exposure compared with the tensile strength, which usually is'hardly affected until the elon- N one 4 gation has nearly all been lest. 4-dodeey1oxy-2hydroxybenzophenone 82 Example 5.-The compositions described in Example 1 were pressed to sheets 0.005 inch thick, and exposed bl V I] in an Atlas Twin-Arc Weather-Ometer, modified by the addition of fluorescent sun lamps as described in Analyti- Percent Exposure w cal Chemistry, 25, 460 (1953), except that twelve Westfigfif duired for mghouse 20-watt fluorescent sun lamps were used instabilizer retained devebpmmt after of brittlestead of eight. The progress of weathering damage was exposure ness (111.) followed by tensile elongation measurements as in Exof400 hr. ample 4. The development of brittleness was also ob- N 0 G00 served by noting the exposure time required to cause the V h films to break when creased once with the exposed surface Modeeyloxy 2 hydroxy enzophenone 60 1 000 on the outside of the crease. Table V gives the results of these tests. Table IX Example 6.Samples of a second set of polyethylene films, prepared like those of Example 5, from the comglh i g ziti il i positions of Example 1, were also exposed in the moditamed alterfied Weather-Ometer. Table VI summarizes the measurestabilizer merits of elongation decay and of embrittlement on these 40 470 hr. 1150 hr. fil BXpOSlll'Q OXPOSUIB Example 7.-Samples of the film of Example 5 were N 20 0 233: Outdoors for months- Table VII shows the A38senatorsaamanasnrsa:1111::1:1:: 85 70 Example 8.--Films of 0001-0002 inch thickness were extruded from the compositions described in Example 1, and were exposed in the modified Weather-Ometer. Deterioration in these thin films took place somewhat more rapidly than in the thicker films described in Example 5. The results of tensile elongation measurements and development of brittleness are shown in Table VIII.

. Example 9.-A high-melting, crystallizable polyethylene having a density of 0.945 was compounded on hot rolls with 2-hydroxy-4-dodecyloxy benzophenone in the proportions of 1 part of stabilizer per parts of polyethylene. The composition was compression-molded to films of 0.005 inch thickness, which were cut into samples 2 /2 x /2 inch in size. These films were exposed in an Atlas Twin-Arc Weather-Ometer modified as described in Example 5 except that ten Westinghouse 20-watt fluorescent sun lamps were used instead of twelve. The progress of weathering damage was followed by elongation measurements by means of an Instron Tensile Tester, using a rate of stretch of 100% per minute. All films were conditioned for 3 days at 73 F. and 50% R. H. before testing. Table IX gives the results.

Example 10.--Additional samples of the films described in Example 9 were also exposed in the same modified Weather-Ometer. Elongationmeasurements were made at a rate of stretch of 2000% per minute. The results are shown in Table X.

Example 11.The polyethylene compositions of EX- ample 9 were formed into sheets ,5 inch thick, and exposed outdoors for 5 months. Infrared absorption of the sheets at 5.8;]. was measured before and after exposure to give a measure of carbonyl formation by photo-oxidation during exposure. The difference was expressed in arbitrary units and recorded in Table XI.

Example 12.-'-Sh'eets as described in Example 11 were cut into sets of 10 samples, 1% x /2 inch in size. These were bent into a U- shape and held in this position in aluminum "channels during exposure, as in Example 3. The

stressed portion of each sample was mounted facing the light, and the samples were exposed outdoors. The exposure times,-in days, required to crack the first sample, half. of the samples (i. e., five samples) and all (ten) tain ed after 14.5 months exposure was 127, and the percentage of original tensile strength retained after 14.5

months exposure was 120. There was no exudation.

While in our examples we have shown the use of samples are listed in Table XII. 5 1% of 2-hydroxy-4-dodecyloxybenzophenone or 2?hy- Table X droxy-4-tetradecyloxybenzophenone, based on the weight of polyolefin, it will be understood that somewhat less P t or considerably more of the stabilizer may be used,.for 32E22 example, from 0.5% to ti stabilizer 22 55 1 3 10 Table XlII.Ultraw0let stabilization of polypropylene afte 410 hi. exposure Oonen. Percent Percent Exposure Exposure of initial initial time time stabifiexural inherent required required None 12 Stabilizer lizer strength viscosity to 4-dodecyloxy-Z-hydroxybenzophenone 80 15 (perleft after left after crack on break on Civtnt )by 113508 25 hosurs' eagles; 0631s;

. ur xpo ure Table XI exposure Carbonyl None 0 23 75 150 4-dodecyloxy-2- Stabilizer {giggggg hydroxybenzopheunits) none 1 95 90 200 700 None. 55 What we claim as our invention and desire to be se- 4'ddecyltlxy'z'hydmxybenmphelwne 4 cured by Letters Patent of the United States is:

25 l. A polyolefin plastic composition comprising a poly- Table XII olefin selected from the group consisting of polyethylene and polypropylene, and, as an agent for inhibiting deteri- Stress-eracki'ng resistance exposure oration 0f the plastic by ultraviolet light, a 2-hydroxy-4- (days) "eqmred alkoxybenzophenone in which the alkoxy group contains Stabilizer from 12 to 14 carbon atoms. 1 Sample 5 samples 10 Samples 2. A polyolefin plastic composition comprising a polyolefin selected from the group consisting of polyethylene and polypropylene, and, as an agent for inhibiting deteri- 4 dodecyloxy- 2 hydroxybenzophenone 535 535 535 oration of the plastic by ultraviolet light, a compound 35 selected from the group consisting of 2-hydroxy-4-do- Example 13. 2-hydroxy-4-dodecyloxybenzophenone was extrusion-compounded into polypropylene of melt index 0.08 and ash content of 0.43%. Temperatures of 475 F. to 500 F. were reached by the plastic mixtures in the vicinity of the extrusion die. The plastic composition was extruded in the form of a strip 0.020 inch thick, which was cut into 2 /2 x /2 inch specimens for testing.

Weathering exposures were made in an Atlas Twin- Arc Weather-Ometer, modified by the addition of ten Westinghouse 20-watt fluorescent sun lamps, as described in Example 9. Weathering damage in the exposed test strips was assessed from time to time during exposure in the following ways:

(a) Measurement of flexural strength by the Tour- Marshall test for stiffness in fiexure (A. S. T. M. D747-43).

(b) Measurement of inherent viscosity of tetralin solutions, 0.25 g. polymer per 100 cc. solvent, at 145 C. The inherent viscosity is defined as lnnr 0.25

where nr is the ratio of viscosity of solution to viscosity of solvent. The polypropylene used had an inherent viscosity of 2.77.

(c) Formation of cracks or breaks when creased with the exposed side on the outside of the crease.

The results are shown in Table XIII.

Example 14.When a composition containing 100 parts by weight of polyethylene of melt index 2 and one part by weight of 2-hydroxy-4-tetradecyloxybenzophenone was pressed into sheets of 0.060 inchthickness and the sheets tested as in Example 1, the carbonyl formation was 9 units at the end of 131 days, 10 units at the end of 1 year, and 20 units at the end of 18 months. There was no color and no exudation either at the beginning of the test or at the end of 18 months.

When samples of the same sheeting were tested as in Example 4, the percentage of original elongation redecyloxybenzophenone and 2-hydroxy-4-tetradecyloxy benzophenone.

3. A polyolefin plastic composition comprising a polyolefin selected from the group consisting of polyethylene and polypropylene, and, as an agent for inhibiting deterioration of the plastic by ultraviolet light, 2-hydroxy-4- dodecyloxy-benzophenone.

4. A polyolefin plastic composition comprising a polyolefin selected from the group consisting of polyethylene and polypropylene, and, as an agent for inhibiting deterioration of the plastic by ultraviolet light, Z-hydroxy- 4-tetradecyloxybenzophenone.

5. A polyolefin plastic composition comprising a polyolefin selected from the group consisting of polyethylene and polypropylene, and, as an agent for inhibiting deterioration of the plastic by ultraviolet light, approxi mately 0.5 to 10%, based on the weight of polyolefin, of 2-hydroxy-4-dodecyloxybenzophenone.

6. A polyethylene plastic composition comprising polyethylene and, as an agent for inhibiting deterioration of the plastic by ultraviolet light, approximately 0.5% to 10%, based on the weight of polyethylene, of 2-hydroxy- 4-dodecyloxy benzophenone.

7. A polypropylene plastic composition comprising polypropylene and, as an agent for inhibiting deterioration of the plastic by ultraviolet light, approximately 0.5 to 10%, based on the weight of polypropylene, of 2-hydroxy-4-dodecyloxy benzophenone.

8. A polyolefin plastic composition comprising a polyolefin selected from the group consisting of polyethylene and polypropylene, and, as an agent for inhibiting deterioration of the plastic by, ultraviolet light, approximately 0.5 to 10% based on the weight of polyolefin, of 2-hydroxy-4-tetradecyloxy benzophenone.

9. A polyolefin plastic composition comprising a polyolefin selected from the group consisting of polyethylene and polypropylene, and, as an agent for inhibiting deterioration of the plastic by ultraviolet light, approximately 1%, based on the weight of polyolefin, of 2-hydroxy-4-dodecyloxy benzophenone.

10. A polyethylene plastic composition comprising polyethylene, and, as an agent for inhibiting deterioration of.th'e plastic by ultraviolet light, approximately 1%, based on the weight of polyethylene, of 2-hydroxy-4-dodecyloxy benzophenone.

- 11. A polypropylene plastic composition comprising polypropylene and, as an agent for inhibiting deterioration of the plastic by ultraviolet light, approximately 1%,

based on the weight of polypropylene, of I2'hydroxy-4- dodecyloxy benzophenone.

12. A polyethylene plastic composition comprising polyethylene and, as anagent for inhibiting deterioration of the plastic by ultraviolet light, approximately 1%, based on the weight of polyethylene, of 2-hydroxy-4- tetradecyloxy benzophenone.

No references cited. 

1. A POLYOLEFIN PLASTIC COMPOSITION COMPRISING A POLYOLEFIN SELECTED FROM THE GROUP CONSISTING OF POLYETHYLENE AND POLYPROPYLENE, AND, AS AN AGENT FOR INHIBITING DETERIORATION OF THE PLASTIC BY ULTRAVIOLET LIGHT, A 2-HYDROXY-4ALKOXYBENZOPHENONE IN WHICH THE ALKOXY GROUP CONTAINS FROM 12 TO 14 CARBON ATOMS. 